TI-BASIC:Getkey Program
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We will be learning about the GetKey command, and how to create a controlled movement in this program.
Contents
Starting Out
There are a few steps to ensure that your program will run smoothly:
Check if you have the RAM to hold a program
Click on 2nd then MEM above the + sign. Make Sure that you have at least 500 RAM too use. If you don't, I suggest you archive something by pressing 2 then 1, then press ENTER on anything that doesn't have a star next to it.
Creating the program
Click the PRGM key then use the right arrow until NEW is highlighted. You should get a screen like this:
PROGRAM NAME=
Go ahead and enter any name you want. Must be only A-Z, no numbers.
Now for the commands
Lets go ahead and put in some commands. By now you should have a general understanding so I'll go through this pretty fast:
PROGRAM:MOVER // Title :ClrHome // Clears screen :1→Y // Sets 1 to Y :1→X // Sets 1 to X :Lbl 1 // Program Divider #1 :Output(X,Y,"O" // Displays the character :getKey→G // Gets the key that the user is pressing :If G=0 // IF G=0 then... :Goto 1 // Go to top (looper) :If G≠0 // If G≠0 then... :ClrHome // Clears the screen :If G=25 // If G=Up then... :Y-1→Y // Y-1 to Y when up is pressed :If G=34 // If G=Down then... :Y+1→Y // Y+1 to Y when down is pressed :If G=24 // If G=Left then... :X-1→X // X-1 to X when left is pressed :If G=26 // If G=Right then... :X+1→X // X+1 to X when right is pressed :If X=0 // If X is less than the screen then... :X+1→X // X+1 to X to stop ERROR:DOMAIN :If Y=0 // IF Y is less than the screen then... :Y+1→Y // Y+1 to Y to stop ERROR:DOMAIN :If X=17 // IF X is greater than the screen then... :X-1→X // X-1 to X to stop ERROR:DOMAIN :If Y=9 // IF Y is greater than the screen then... :Y-1→Y // Y-1 to Y to stop ERROR:DOMAIN :Goto 1 // Goes up to the top (looper)
Result
The user will be able to move a little circle around the screen.
Conclusion
Way to go you made your first getKey program!
Optionals
You can make your circle teleport to the other side of the screen if you change this part of the program.
... :If X=0 // If X is less than the screen then... :X+16→X // Move X to right side of the screen :If Y=0 // IF Y is less than the screen then... :Y+8→Y // Move Y to bottom of the screen :If X=17 // If X is greater than the screen then... :X-16→X // Move X to left side of the screen :If Y=9 // If Y is greater than the screen then... :Y-8→Y // Move Y to top of the screen :Goto 1 // Goes up to the top (looper)
